| 1376 | Animals |
| 1043 | Perches |
| 364 | Female |
| 254 | Male |
| 215 | Fishes |
| 204 | Water Pollutants, Chemical |
| 200 | Fresh Water |
| 172 | Fish Diseases |
| 130 | Species Specificity |
| 123 | Environmental Monitoring |
| 115 | Phylogeny |
| 109 | Liver |
| 105 | Chickens |
| 101 | Molecular Sequence Data |
| 101 | Housing, Animal |
| 96 | Perciformes |
| 89 | Ecosystem |
| 87 | Time Factors |
| 81 | Humans |
| 80 | Behavior, Animal |
| 77 | Seasons |
| 70 | Cyprinidae |
| 69 | Retina |
| 65 | Base Sequence |
| 64 | Genetic Variation |
| 63 | Lakes |
| 62 | Gills |
| 59 | Temperature |
| 56 | Predatory Behavior |
| 56 | Mercury |
| 54 | Sequence Analysis, DNA |
| 53 | Reproduction |
| 53 | DNA, Mitochondrial |
| 50 | Muscles |
| 47 | Host-Parasite Interactions |
| 46 | Population Dynamics |
| 46 | Animal Welfare |
| 45 | Animal Husbandry |
| 45 | Amino Acid Sequence |
| 44 | Rivers |
| 44 | Evolution, Molecular |
| 44 | Diet |
| 43 | Food Chain |
| 42 | Population Density |
| 42 | Microscopy, Electron |
| 42 | Microsatellite Repeats |
| 42 | Environmental Exposure |
| 42 | Biological Evolution |
| 41 | Models, Biological |
| 40 | Polymerase Chain Reaction |
| 40 | Oviposition |
| 40 | Larva |
| 40 | Body Size |
| 40 | Analysis of Variance |
| 39 | Feeding Behavior |
| 38 | Trematode Infections |
| 38 | Esocidae |
| 35 | Tissue Distribution |
| 35 | Sweden |
| 34 | Geography |
| 34 | Environment |
| 33 | Trematoda |
| 33 | Brain |
| 32 | Gene Expression Regulation |
| 32 | Fish Proteins |
| 32 | Finland |
| 32 | Cadmium |
| 32 | Body Weight |
| 32 | Adaptation, Physiological |
| 31 | Trout |
| 31 | Food Contamination |
| 29 | Sequence Alignment |
| 29 | Seawater |
| 29 | Neurons |
| 29 | Light |
| 29 | Hydrogen-Ion Concentration |
| 29 | Copper |
| 28 | Prevalence |
| 28 | Ovum |
| 28 | Genetics, Population |
| 28 | Cloning, Molecular |
| 27 | Polychlorinated Biphenyls |
| 27 | Muscle, Skeletal |
| 26 | Ovary |
| 26 | Fisheries |
| 26 | Dopamine |
| 25 | Stress, Physiological |
| 25 | RNA, Messenger |
| 25 | Poultry Diseases |
| 25 | Oocytes |
| 25 | Oncorhynchus mykiss |
| 25 | Helminthiasis, Animal |
| 25 | DNA Primers |
| 25 | Aquaculture |
| 23 | Zinc |
| 23 | Water Pollutants |
| 23 | Dose-Response Relationship, Drug |
| 23 | Carps |
| 23 | Biological Markers |
| 23 | Bass |
| 22 | Sequence Homology, Amino Acid |
| 22 | Kidney |
| 22 | Gonads |
| 22 | Geologic Sediments |
| 22 | Birds |
| 21 | Ontario |
| 21 | Metals, Heavy |
| 21 | DNA, Complementary |
| 21 | Acanthocephala |
| 20 | Sexual Behavior, Animal |
| 20 | Selection, Genetic |
| 20 | Electrophoresis, Polyacrylamide Gel |
| 20 | Eggs |
| 20 | Calcium |
| 19 | Polymorphism, Genetic |
| 19 | Photoreceptor Cells |
| 19 | Organ Size |
| 19 | Insecticides |
| 19 | Immunohistochemistry |
| 19 | Hydrocortisone |
| 19 | Histocytochemistry |
| 19 | Biomechanical Phenomena |
| 18 | Sex Factors |
| 18 | Methylmercury Compounds |
| 18 | Metals |
| 18 | Locomotion |
| 17 | Zooplankton |
| 17 | Testosterone |
| 17 | Swimming |
| 17 | Salmonidae |
| 17 | Reverse Transcriptase Polymerase Chain Reaction |
| 17 | Lizards |
| 17 | Kinetics |
| 17 | Intestines |
| 17 | Energy Metabolism |
| 17 | DNA |
| 17 | Cytochrome P-450 CYP1A1 |
| 17 | Circadian Rhythm |
| 17 | Bone and Bones |
| 17 | Age Factors |
| 16 | Water Pollution, Chemical |
| 16 | Sex Characteristics |
| 16 | Regression Analysis |
| 16 | Rats |
| 16 | Quebec |
| 16 | Oceans and Seas |
| 16 | Models, Genetic |
| 16 | Conservation of Natural Resources |
| 16 | Cestoda |
| 16 | Bayes Theorem |
| 15 | Testis |
| 15 | Social Behavior |
| 15 | Risk Assessment |
| 15 | Poland |
| 15 | Photic Stimulation |
| 15 | Motor Activity |
| 15 | Membrane Potentials |
| 15 | In Vitro Techniques |
| 15 | Haplotypes |
| 15 | France |
| 15 | Chromatography, High Pressure Liquid |
| 15 | Cestode Infections |
| 15 | Cell Nucleus |
| 15 | Alleles |
| 14 | Superior Colliculi |
| 14 | Spleen |
| 14 | Skin |
| 14 | Retinal Rod Photoreceptor Cells |
| 14 | Parasitic Diseases, Animal |
| 14 | Mitochondria |
| 14 | Life Cycle Stages |
| 14 | Genotype |
| 14 | Czech Republic |
| 14 | Biodiversity |
| 14 | Aggression |
| 14 | Adult |
| 13 | Water |
| 13 | United States |
| 13 | Triiodothyronine |
| 13 | Spermatozoa |
| 13 | Sequence Homology, Nucleic Acid |
| 13 | Russia |
| 13 | Retinal Cone Photoreceptor Cells |
| 13 | Random Allocation |
| 13 | Organ Specificity |
| 13 | Middle Aged |
| 13 | Microscopy, Electron, Scanning |
| 13 | Mice |
| 13 | Linear Models |
| 13 | Helminths |
| 13 | Gene Expression Profiling |
| 13 | Feathers |
| 13 | Estradiol |
| 13 | Enzyme-Linked Immunosorbent Assay |
| 13 | Eating |
| 13 | Dark Adaptation |
| 13 | Australia |
| 13 | Aging |
| 12 | Weight Gain |
| 12 | Video Recording |
| 12 | Proteins |
| 12 | Pesticide Residues |
| 12 | Oxygen Consumption |
| 12 | Lipid Metabolism |
| 12 | Industrial Waste |
| 12 | Europe |
| 12 | Color Perception |
| 12 | Cells, Cultured |
| 12 | Adolescent |
| 11 | gamma-Aminobutyric Acid |
| 11 | Synapses |
| 11 | Radioimmunoassay |
| 11 | Phenotype |
| 11 | Nesting Behavior |
| 11 | Molecular Weight |
| 11 | Metallothionein |
| 11 | Likelihood Functions |
| 11 | Intestinal Mucosa |
| 11 | Great Lakes Region |
| 11 | Gonadotropin-Releasing Hormone |
| 11 | Gonadal Steroid Hormones |
| 11 | Goldfish |
| 11 | Germany |
| 11 | Genome |
| 11 | Flight, Animal |
| 11 | Eukaryota |
| 11 | Cyclic AMP |
| 11 | Crustacea |
| 11 | Color |
| 11 | Cesium Radioisotopes |
| 11 | Cell Line |
| 11 | Animal Feed |
| 10 | Vision, Ocular |
| 10 | Tibia |
| 10 | Sperm Motility |
| 10 | Spectrophotometry, Atomic |
| 10 | Risk Factors |
| 10 | Rabbits |
| 10 | Protozoan Infections, Animal |
| 10 | Principal Component Analysis |
| 10 | Pigmentation |
| 10 | Oxygen |
| 10 | Ovarian Follicle |
| 10 | Nitrogen Isotopes |
| 10 | Lead |
| 10 | Kainic Acid |
| 10 | Hydrocarbons, Chlorinated |
| 10 | Glutamic Acid |
| 10 | Genetic Markers |
| 10 | Feces |
| 10 | Fatty Acids |
| 10 | Embryo, Nonmammalian |
| 10 | Ecology |
| 10 | Digestive System |
| 10 | Darkness |
| 10 | DDT |
| 10 | Cell Division |
| 10 | Cattle |
| 10 | Catfishes |
| 10 | Carbon Isotopes |
| 10 | Blotting, Western |
| 10 | Africa |
| 10 | Africa, Eastern |
| 9 | Wisconsin |
| 9 | Waste Water |
| 9 | Vitellogenins |
| 9 | Staining and Labeling |
| 9 | Retinal Ganglion Cells |
| 9 | Parasites |
| 9 | Norway |
| 9 | Nickel |
| 9 | Hot Temperature |
| 9 | Heterozygote |
| 9 | Great Britain |
| 9 | Gene Expression |
| 9 | Fluorescent Antibody Technique |
| 9 | Epithelium |
| 9 | Electrophysiology |
| 9 | DNA, Ribosomal |
| 9 | Cytochrome P-450 Enzyme System |
| 9 | Competitive Behavior |
| 9 | Chromosome Mapping |
| 9 | Canada |
| 9 | Bivalvia |
| 9 | Biometry |
| 9 | Aromatase |
| 9 | Aged |
| 9 | Adaptation, Ocular |
| 8 | Water Pollution |
| 8 | Waste Disposal, Fluid |
| 8 | Visual Pathways |
| 8 | Trees |
| 8 | Switzerland |
| 8 | Selenium |
| 8 | Seafood |
| 8 | Rhabdoviridae Infections |
| 8 | Reproducibility of Results |
| 8 | Receptors, GABA |
| 8 | Phylogeography |
| 8 | Photoperiod |
| 8 | Phosphorylation |
| 8 | New York |
| 8 | Models, Statistical |
| 8 | Mexico |
| 8 | Isoenzymes |
| 8 | Introns |
| 8 | Insulin-Like Growth Factor I |
| 8 | Hybridization, Genetic |
| 8 | Growth Hormone |
| 8 | Genetic Speciation |
| 8 | Gene Flow |
| 8 | Flounder |
| 8 | Eye Proteins |
| 8 | Erythrocytes |
| 8 | Equipment Design |
| 8 | Disorders of Sex Development |
| 8 | Cytochrome b Group |
| 8 | Chlorides |
| 8 | Cell Membrane |
| 8 | Cell Differentiation |
| 8 | Cell Count |
| 8 | Cannibalism |
| 8 | Brain Chemistry |
| 8 | Blood Glucose |
| 8 | Antibodies |
| 8 | Air Sacs |
| 7 | Xenopus |
| 7 | Xenopus laevis |
| 7 | Water-Electrolyte Balance |
| 7 | Water Pollutants, Radioactive |
| 7 | Vocalization, Animal |
| 7 | Vitellogenesis |
| 7 | Ultraviolet Rays |
| 7 | Tilapia |
| 7 | Survival Analysis |
| 7 | Snails |
| 7 | Sexual Maturation |
| 7 | Sex Differentiation |
| 7 | Serotonin |
| 7 | Sensory Thresholds |
| 7 | Salmon |
| 7 | Preoptic Area |
| 7 | Posture |
| 7 | Polycyclic Hydrocarbons, Aromatic |
| 7 | Plankton |
| 7 | Patch-Clamp Techniques |
| 7 | Ovulation |
| 7 | Optic Nerve |
| 7 | Nematoda |
| 7 | Muramidase |
| 7 | Mortality |
| 7 | Models, Theoretical |
| 7 | Microsomes, Liver |
| 7 | Liver Abscess, Amebic |
| 7 | Italy |
| 7 | Invertebrates |
| 7 | Introduced Species |
| 7 | Hypergravity |
| 7 | Hydroxyprogesterones |
| 7 | Gonadotropins |
| 7 | Glycoproteins |
| 7 | Glutamates |
| 7 | Glucosephosphate Dehydrogenase |
| 7 | Gene Frequency |
| 7 | Gastrointestinal Contents |
| 7 | Environmental Pollutants |
| 7 | England |
| 7 | Endocrine System |
| 7 | Disease Outbreaks |
| 7 | Cytoplasmic Granules |
| 7 | Cytochromes b |
| 7 | Cues |
| 7 | Copepoda |
| 7 | Child |
| 7 | Breeding |
| 7 | Body Constitution |
| 7 | Blotting, Southern |
| 7 | Blotting, Northern |
| 7 | Bird Diseases |
| 7 | Biotransformation |
| 7 | Antibodies, Monoclonal |
| 7 | Animals, Wild |
| 7 | Amino Acids |
| 7 | Agonistic Behavior |
| 6 | Wing |
| 6 | Weightlessness |
| 6 | Visual Fields |
| 6 | Vertebrates |
| 6 | Thyroid Gland |
| 6 | Tanzania |
| 6 | Spectrophotometry |
| 6 | Spatial Behavior |
| 6 | Smell |
| 6 | Smegmamorpha |
| 6 | Sewage |
| 6 | Sensitivity and Specificity |
| 6 | Receptors, Glutamate |
| 6 | RNA, Ribosomal, 16S |
| 6 | Protein Structure, Tertiary |
| 6 | Ponds |
| 6 | Plants |
| 6 | Pituitary Gland |
| 6 | Phenols |
| 6 | Paper |
| 6 | Oxidoreductases |
| 6 | Odors |
| 6 | Novirhabdovirus |
| 6 | North America |
| 6 | Nerve Fibers |
| 6 | Myocardium |
| 6 | Muscle Proteins |
| 6 | Minnesota |
| 6 | Melanophores |
| 6 | Magnesium |
| 6 | Lymphocytes |
| 6 | Lipids |
| 6 | Lighting |
| 6 | Lectins |
| 6 | L-Lactate Dehydrogenase |
| 6 | Isopoda |
| 6 | Intestinal Diseases, Parasitic |
| 6 | Insects |
| 6 | Immunoenzyme Techniques |
| 6 | Ictaluridae |
| 6 | Heterophyidae |
| 6 | Gram-Negative Bacterial Infections |
| 6 | GABA Antagonists |
| 6 | Foot Diseases |
| 6 | Floors and Floorcoverings |
| 6 | Facility Design and Construction |
| 6 | Eye |
| 6 | Eye Movements |
| 6 | Exons |
| 6 | Electron Transport Complex IV |
| 6 | Ectoparasitic Infestations |
| 6 | Demography |
| 6 | Daphnia |
| 6 | DNA Virus Infections |
| 6 | DNA Adducts |
| 6 | Climate Change |
| 6 | Chromatography, Ion Exchange |
| 6 | Chromatography, Gel |
| 6 | Cell Size |
| 6 | Cats |
| 6 | Bone Density |
| 6 | Biomass |
| 6 | Binding Sites |
| 6 | Bile |
| 6 | Baltic States |
| 6 | Axons |
| 6 | Argentina |
| 6 | Anoxia |
| 6 | Animal Nutritional Physiological Phenomena |
| 6 | Acclimatization |
| 5 | Water Movements |
| 5 | Visual Perception |
| 5 | Virus Replication |
| 5 | Virus Diseases |
| 5 | Up-Regulation |
| 5 | Thyroxine |
| 5 | Stochastic Processes |
| 5 | Spores |
| 5 | Spinal Cord |
| 5 | Sodium-Potassium-Exchanging ATPase |
| 5 | Social Environment |
| 5 | Skates (Fish) |
| 5 | Semen |
| 5 | Seeds |
| 5 | Ranavirus |
| 5 | Protozoan Infections |
| 5 | Protein Binding |
| 5 | Pregnenolone |
| 5 | Pesticides |
| 5 | Passeriformes |
| 5 | Parvalbumins |
| 5 | Oogenesis |
| 5 | Nova Scotia |
| 5 | Norepinephrine |
| 5 | Nitrogen |
| 5 | Nephelometry and Turbidimetry |
| 5 | Nematode Infections |
| 5 | Multivariate Analysis |
| 5 | Movement |
| 5 | Mining |
| 5 | Microsporidiosis |
| 5 | Microscopy, Electron, Transmission |
| 5 | Microcystins |
| 5 | Michigan |
| 5 | Mathematics |
| 5 | Mass Spectrometry |
| 5 | Maryland |
| 5 | Lipopolysaccharides |
| 5 | Lipid Peroxidation |
| 5 | Leukocyte Count |
| 5 | Lethal Dose 50 |
| 5 | Least-Squares Analysis |
| 5 | Lactic Acid |
| 5 | Isotope Labeling |
| 5 | Iridoviridae |
| 5 | Ion Channels |
